This invention relates to topical compositions having a unique multivesicular emulsion characteristic.
Topical delivery systems are, of course, known and they run the gambit of physical characteristics from solids, to various creams of varying degrees of lubricity, to ointments and to lotions. A key for a successful topical delivery systems is, in fact, how successful they are at delivery of the so-called active. For example, with most topical actives there is a high or so-called spike release immediately after application followed by a dramatic decrease in release over time. This is not satisfactory since the initial spike dose is often too high and there is a lack of sustained release over time, resulting in minimized effectiveness. Moreover, not only is lack of sustained release and the observation of a spike release a problem, but often with spike releases, there is overdosing in spot areas which can cause skin irritation.
The topical products susceptible to both spike dosing and skin irritation can occur in a variety of physical forms, including solids, liquids, suspensions, semisolids (such as creams, gels, lotions, pastes or xe2x80x9csticksxe2x80x9d), powders or finely dispersed liquids such as sprays or mists. Examples of topical products commonly classified as xe2x80x9ccosmeticsxe2x80x9d include skin care products such as moisturizing creams and lotions, and xe2x80x9ctreatment cosmeticsxe2x80x9d such as exfoliants and/or skin cell renewal agents; fragrances such as perfumes and colognes, and deodorants; shaving-related products such as creams, xe2x80x9cbracersxe2x80x9d and aftershaves; depilatories and other hair removal products; skin cleansers, toners and astringents; pre-moistened wipes and washcloths; tanning lotions and sunscreens; bath products such as oils; eye care products such as eye lotions and makeup removers; foot care products such as powders and sprays; skin colorant and make-up products such as foundations, blushes, rouges eye shadows and lines, lip colors and mascaras; lip balms and sticks; hair care and treatment products such as shampoos, conditioners, colorants, dyes, bleaches, straighteners, and permanent wave products; baby products such as baby lotions, oils, shampoos, powders and wet wipes; feminine hygiene products such as deodorants and douches; skin or facial peels applied by dermatologists or cosmeticians; and others.
Examples of topical products commonly classified as xe2x80x9ctopical actives: are many and varied, and include over-the-counter and/or prescription products such as antiperspirants, insect repellants, sunscreens and sunburn treatment, anti-acne agents, antibiotics, therapeutic retinoids, anti-dandruff agents, external analgesics such as capsaicin products, topical contraceptives, topical delivery systems, suppositories and enemas, hemorrhoid treatments, vaginal treatments, lozenges, and many other products with therapeutic or other effects. Other topical products include hand, facial and body soaps and detergents and other forms of skin cleansers, as well as household detergents and many other household products such as solvents, propellants, polishes, lubricants, adhesives, waxes and others which are either applied topically or are topically exposed to the body during normal use.
This invention is useful for topical cosmetics, topical treatment cosmetics and for topical actives.
Accordingly, it is a primary objective of the present invention to provide topical delivery compositions which contain a pharmaceutically/pharmacologically active agent and which do not have the normally attended problem of spike release nor the problem of ineffective sustained release.
Importantly, the invention also relates to a method of making topical delivery compositions which assures that the emulsion containing the pharmaceutically/pharmacologically active agent will be a multivesicular emulsion as that term is defined herein.
The method and manner of accomplishing each of the above objectives as well as others will become apparent from the detailed description of the invention which follows herein after.
The present invention relates to a method of preparing a topical delivery composition and to the composition itself. The composition can be characterized as a multivesicular emulsion which may contain a pharmaceutically/pharmacologically active agent. The emulsifier, which if used in the way described herein, provides a multivesicular emulsion, is preferably a quaternary amine salt such as behentrimonium methosulfate used at a level of from 0.1% by weight of the total composition to 30% by weight of the total composition. It""s preferred level is from 0.5% by weight of the total composition to 5% by weight of the total composition. In the method, the pharmaceutically/pharmacologically active agent is mixed with the most compatible phase for it (either the oil phase or the water phase) and thereafter it is high sheer mixed with a quaternary amine salt emulsifier. In addition, the pharmaceutically/pharmacologically active agent may be suspended in the emulsion where it becomes entrapped within the vesicle. In these cases, a multivesicular emulsion forms which avoids spike release and yet has long term sustained release. The composition itself surprisingly affects the biophysical properties of the skin such as increased blood flow, reduction of transepidermal water loss, and increase of skin hydration.